It turns out Australia’s standard isn’t 235 volts plus or minus 8%. It’s actually 230 volts +10% or -6%, giving a range of 216.2 to 253 volts. You may be wondering why the plus goes all the way up to 10% and the minus only goes down to 6%. Well, that’s because Australia really wanted to be able to say we had changed from our old standard of 240 volts down to the much more common 230 volts that is an international standard.
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The downside is it’s really difficult for a grid designed for an average of 240 volts to get down to an average of 230. We only had two sensible options:
1. Do the hard work and spend the large amount of money required to make the change.
2. Admit there would be a long transition period where the voltage would average between 230 and 240 volts.
So, of course, we instead decided to:
3. Half arse it.
We lowered the average voltage as far as it would easily go with existing grid infrastructure and then claimed to have met the standard by abusing the concept of plus or minus and allowing a big plus 10% with a considerably smaller minus 6%.
We’ve been slowly working our way down further as old equipment is replaced. At the current rate, in South Australia, this process will take around 250 years. Mind you, we’ll have to pick up the pace at some point when aging equipment starts falling apart.